1) Field
The general inventive concept relates to a field-effect transistor and a sensor based on the field-effect transistor.
2) Description of the Related Art
A field-effect transistor (“FET”) typically includes a source region that supplies electrons or holes, a drain region that depletes the electrons or the holes supplied from the source region, and a gate region that controls a flow of the electrons or the holes. The gate region may control the flow of the electrons or the holes using an electric field generated by the voltage applied to the gate.
The size of the conventional FET has been substantially reduced. Recently, chips including about 100 million transistors integrated thereon have been developed, wherein each of the 100 million transistors is about 50 nanometers (nm) in size. However, as the size of the transistor is reduced to below about 50 nm, the miniaturization of the FET may encounter a fundamental physical limitation. Accordingly, new elements such as silicon-on-insulator (“SOI”) transistors, multi-gate transistors, and schottky transistors, for example, have been studied and developed to overcome fundamental physical limitation on further size reduction.
In addition, the FET may include a single-walled carbon nanotube having a semiconductor characteristic, e.g., a carbon nanotube transistor, having relatively high charge mobility. Researches on a high sensitivity sensor using the carbon nanotube have recently been made due to the characteristics of the carbon nonotube such as, e.g., a high charge mobility of the carbon nanotube transistor and the characteristic that all constituent atoms are located on a surface of the carbon nanotube and a chemical/biological reaction occurring on the surface of the carbon nanotube transistor is detected. A carbon nanotube-based sensor may measure the migration or charged state of charges in a chemical/biological reaction. Accordingly, the carbon nanotube-based sensor is based on a label-free method and has a short detection time. In addition, the cost of producing the carbon nanotube-based may be substantially reduced using a semiconductor process.
Recent developments in carbon nanotube growth and separation techniques may suggest that applications of the carbon nanotube, which are currently limited to bulk materials and composite materials, will be expanded to carbon nanotube-based electronic elements and sensors.